The present invention relates to a method and apparatus for remotely sensing, monitoring, and recording the temperature of acrolein in a storage tank. More specifically, the present invention uses a commercially available global positioning system (GPS) receiver/transmitter to communicate the temperature of acrolein in the storage to a remote base station via a satellite in order to alert users of a dangerous condition within the storage tank and initiate appropriate responsive action. Solar powered, rechargeable batteries supply power to the temperature sensor/transmitter, the GPS transmitter/receiver, and the response mechanism at the storage tank.
The efficient reduction and removal hydrogen sulfide (H2S) from produced fluids in oil and gas operations has considerable environmental impact. One of the ways of minimizing H2S is the addition of chemical scavengers directly to production containing oil, water, and gas. Acrolein (2-propenal) has been shown to be an effective chemical scavenger in oil and gas production. Thus, acrolein is often stored at oil/gas production sites for use in treating the produced fluids. Many times such sites are in remote locations which makes monitoring of the acrolein storage tanks difficult. It will be understood that acrolein storage tanks are also used in the agriculture market (aquatic herbicide and/or nematicide) and are thus within the scope of the present invention.
Since acrolein is a highly reactive chemical, it has the potential to undergo violent exothermic polymerization. In extreme cases, the polymerization can occur with enough force to rupture the storage tank resulting in release of hazardous chemical and metal fragments from the tank. Thus, monitoring the condition of stored acrolein to detect dangerous polymerization is an important safety aspect where it is used in hydrocarbon production. Such polymerization may be detected by a change in the liquid acrolein temperature.
Polymerization may occur for a number of reasons, including contamination with incompatible chemicals, heat above 200° Fahrenheit, or exposure to light or gamma radiation. Contamination with various chemicals may initiate polymerization radically, anionically or cationically. The type of polymerization reaction that occurs depends on the specific contaminant.
Radical polymerization is typically induced by oxygen contamination and can be minimized by a polymerization inhibitor, such as hydroquinone. As acrolein product in a vessel ages, hydroquinone content can decrease resulting in an increased likelihood that polymerization will occur.
Ionic polymerization may occur if contaminants are introduced into the product container by connection of contaminated equipment or by intrusion of process fluids flowing back into the storage vessel. Contaminants that typically are associated with ionic polymerization of acrolein are alkaline compounds, such as caustic soda, ammonia, and amines, or by mineral acids, such as concentrated sulfuric acid. Hydroquinone is not effective as an inhibitor of ionic polymerization.
Radical polymerization principally proceeds across the vinyl functional group and ionic polymerization results in additions at the carbonyl group as shown below.

Ionic polymerization can occur very rapidly with little opportunity to mitigate any reaction if large quantities of contaminants are introduced to the acrolein container. However, if the polymerization is due to water contamination, oxygen or low concentrations of ionic contaminants, the reaction will typically proceed slowly enough to allow response measures to be implemented. The temperature increase from the polymerization reaction may result in temperatures as high as 400° Fahrenheit. However, it may take several days or hours to reach these extreme temperatures.
During the polymerization process, the temperature of the bulk liquid increases. The present inventive method and apparatus will provide notification to users that the acrolein is starting to polymerize. This notification will allow for response before a tank failure has occurred. This response may include introduction of chemicals to the tank to stop polymerization (an emergency buffer solution comprised of 84% acetic acid, 8% hydroquinone, 8% anhydrous sodium acetate), spraying cooling solution on the tank to slow the polymerization reaction, removal of the tank to a safe location or evacuation of personnel to a safe distance away from the tank.
The current method of solving the problem addressed by the present invention consists of filling the storage tank and monitoring the temperature for three days prior to shipment. If there are contaminates in the acrolein, corrective action may be taken before shipment of the storage tank. There are no controls available to allow detection of an exothermic reaction once the tank has been shipped or is in use in the field.